The semiconductor industry has experienced rapid growth due to improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from shrinking the semiconductor process node (e.g., shrinking the process node towards the sub-20 nm node).
Memory circuits are facing tighter requirements for power, performance, and area. Nonvolatile memory is a form of memory circuit that retains its programmed or erased state regardless of whether power is applied to the memory circuit. Types of nonvolatile memory include: resistive random-access memory (RRAM or ReRAM), magnetoresistive random-access memory (MRAM), phase-change random-access memory (PCRAM), and conductive-bridging random-access memory (CBRAM), among others. An RRAM bit cell is programmed by forming a filament(s) or conductive path in a dielectric medium, and erased by breaking the filament(s). The programmed (or “set”) RRAM bit cell is able to conduct much higher current than the erased (or “reset”) RRAM bit cell. The relative current level of the RRAM bit cell is read by a sense amplifier to generate a binary bit corresponding to the state (set or reset) of the RRAM bit cell.